Hitherto, a conventional adhesive sheet has been used as a management or display label affixed onto electronic parts or the like. However, in recent years, demand has arisen for electronic parts meeting high flame retardant standards. Thus, such a management label is required to have high flame resistance.
Under such circumstances, a substrate of an adhesive sheet which is used as the aforementioned label or an adhesive used therein has come to be made of various flame-retardant materials developed through different techniques. However, even when a substrate made of a flame-retardant material is employed, in the case where a coating layer made of a material such as polyester or polyurethane is employed as a print-image-receiving layer, the flame resistance of the label provided therefrom problematically decreases.
There has been known a heat-resistant coating layer for receiving printed images, the layer containing an inorganic powder and an organic binder in specific amounts (see Patent Document 1). Although the coating layer has heat resistance, flame resistance of the coating layer is not ensured.
Another print-image-receiving layer made from halo-polyolefin or polyvinyl chloride has excellent flame resistance and printability. However, due to presence of halogen, electronic circuits are damaged by corrosion and halogen-containing gas, resulting in a malfunction of the electronic parts. Therefore, such a print-image-receiving layer encounters difficulty in employment as a management label affixed onto electronic elements, which is problematic. In addition, a toxic gas may generate from halogen, and such a toxic gas is also problematic when the print-image-receiving layer is used as a label other than a management or display label affixed onto electronic parts.